Boring tool



W. K. YOUNG BORING 'roorJ Jan. 14, 1941.

Filed March 22, 1939 /N VEN TOR TTORNEYS.

Patented Jan. 14, 1941 PATENT. OFFICE 2,228,498 i 1 BORING Toor.`

William K.. Young, .Detroit,:Mich., assignor to Eclipse Counterbore Company, Detroit, Mich., a corporation of Michigan Application March 22, 1939, Serial No. 263,468-

19 claims.

ticularly to that type thereof having readily removable vand replaceable blades capable of being adjusted in position during use, the principal ob- 5 ject being the provisionof a tool of this` typeTin which the cutter blades-may .be expanded while received within a bore and maintained in expanded condition while Ibeing fed axially of the bore. Other objects of the invention include the provision of a boring tool hav-ing one or more transversely disposed cutter blades supported and driven thereby together with novel means for effecting movement of the cutteriblade or blades in a radial direction during operation of thetool;

scribed having a novel and efficient form of connection between the cutter blade or blades and the operating or controlling means therefor so constructed and arranged as to minimize Athe weakening of the corresponding` por-tion of the boring toolfstructure and thereby permitting th-e provision ofv a practical boring tool of material'ly smallerdiameter than heretofore possible; the provision of a .boring tool provided with one or m-ore blades transversely adjustable with respect thereto so constructed and arranged as to permit the insertion of the cutter blade into a bore,

- movement of the tool axially of the bore Where-- by -to machine a recess therein; the provision of a construction as above described in which the expansion of the cutter blade in the bore occurs automatically as a function of the axi-a-l movement of the boring tool; the provision of a construction as above described in which means are provided for automatically expanding the cutter blade and maintaining itin expanded condition during a predetermined travel of the boring tool in an axial direction and automatically collapsing or withdrawing the cutter blade upon completion of said predetermined axial travel; the provision of a boring tool as above described in which manually adjustable means are provided for varying the effective diameter or swing of .the expanded cutter blade, not only to permit the diameter of the bore machined there- 'by to be controlled within desirable limits, but.

65 thereon; to provide a boring tool of the type the provision of a boring tool of the type de' (c1. 'zr-58) described in'whi'ch means are provided for accurately and visually controlling they effective swing or diameter of the cutter bllade whereby variations in the diameters of b-ores machined thereby maybe varied by manipulating the ad- 5 justments and without requiring checking of the diameter of the bore after each such adjustment; and the provision of a boring tool that is relatively simple in construction, eflicient in op' eration and relatively economical to produce.

The above being among the objects of the present invention the same. consists in certain novel features of construction and combinations of parts .to be hereinafter described with reference to theacc-ompanying drawing, and then claimed, having .the above and other objects in view.

In Vthe accompanying drawing which illustrates a suitable embodiment of the present invention, and in which like numerals refer to like parts throughout the several different views,-

Fig. l is a fragmentary perspective view of a boring machine or mill illustrating a rboring toolv embodying the present invention suitably mounted therein and in operative relation with respect to a piece of work supported in the mfachine;

Fig. 2 is an eniarged side elevational view of the boring tool illustrated in the boring machine or mill shown in Fig. 1;

Fig. 3 is an enlarged sec-tional view taken axially .through the boring tool shown in Fig. 2, as on the line 3 3 thereof, and illustrating certain parts of the boring machine or milll, work and expansion collar, shown in conjunction therewith in Fig. 1, arranged in operativerelation with respect thereto, the various parts of the boring tool being shown in the position assumed when the cutter blade is retracted; y

Fig. 4 is a view similar to Fig. 3` but illustratfing the various parts of the boring tool in a po- 40 sition in which the cutter blade is moved to fully expanded position l Fig. 5 is an enlarged transverse sectional view taken on the line 5`5 of Fig. 3; and,

Fig. 6 is an enlarged transverse sectional view taken on the line 6-6 of Fig. 3. I

v While a boring tool constructed in accordance with the present invention may be employed for machining a bore of constant diameter throughout, it is particularly designed for and is particularly valuable in connectionv with the machining of bores having stepped surfaces. In other words, it is particularly valuable in conl necticn with the machining of relief enlargements, grooves ori the like in the bores of mamachining relation with respect to the interior surfaces of the bore, and maintaining such expanded condition during continued axial travel of the tool in the bore whereby to permit the bore to be relieved over a predetermined distance of the length thereof. The mechanism provided is such as to accurately control the amount of radial movement of the blade upon expansion and further is such as to permit the initial or inoperative position or location of the cutting edges of the blade to be manually adjusted with respect to the axis of the tool whereby the effective diameter of the blade when expanded may be accurately and positively controlled and adjusted in service. y

Referring now to the accompanying drawing and particularly to Fig. l thereof a conventional type of boring machine or boring mill is shown to which the present invention is applicable, it being understood in this respect, however, that the present invention is applicable to any conventional type of boring machine or boring mill, drill press, or the like and regardless of Whether the Work is fed toward the tool or the tool is fed toward the work, and whether the tool or the work is rotated. The particular boring machine illustrated in Fig. 1 includes a supporting base structure generally indicated at I0 provided with a driving head indicated generally at l2. thereon and including a rotatable driving spindle I4. The base I0 is also provided with conventional slides upon which a suitable table or work support I8 is slidably mounted for feeding or other movement in a direction`parallel to the axis of the spindle I4. The particular table I8 shown is provided with suitable and conventional means for receiving, locating and securing a piece of work such as 20 in xed relation thereto, an outboard bearing support or guide 22 for the boring bar here indicated generally at 24, and suitable supports 26 fixed to the table I8 and supporting a stop collar 28 in preferably fixed position thereon. It will be understood that the boring bar 24 is received by the spindle I4 in axially aligned relation with respect thereto and cooperates therewith in a conventional manner for receiving driving movement therefrom.

Boring bars constructed inaccordance with the present invention may be 'provided with more than one cutter blade, projecting in the same or opposite directions from the tool, simply by providing the required number of apertures in the body portion of the tool required to receive such blades and by' forming the blade actuating plunger for cooperation with such blades. For the purpose of simplicity in d escription and explanation, however, the tool shown by way of illustration is equipped with a single cutter blade, the manner in which additional cutter blades may be provided thereby being made clear to those skilled in the art.

The boring bar itself as illustrated in the drawing comprises a main body portion of circular cross-sectional configuration throughout having at one end thereof a hollow shank 36 which may be of any suitable size or shape adapting it for reception in a driving -spindle 0r the like, an adjacent portion 32. shown of slightly greater diameter than the portion 30 smaller diameter than the portion 32 so astov form a radially directed annular shoulder 36 at its junction therewith, a next adjacent portion k38 shown of smaller diameter than the portion 34\but which obviously, under some circumstances at least, may be of a diameter not to exceed the diameter of the portion `34, and finally and preferably but not necessarily, an opposite end or pilot portion 40 which may be of the same or smaller diameter than the portion 38 but which is shown as of smaller diameter particularly for the purpose of illustration. The shank 30 is provided with a concentric cylindrical bore 42 which continues at full diameter through the portion 32 and into the portion 3'4 to a point adjacent the outer end thereof, as illustrated in Figs. 3 and 4, where it joins with a smaller and continuing bore 44 concentric with the axis of the main body portion of the tool and which extends down into the pilot portion 40 as illustrated. Freely. slidably but relatively closely received `within the bore 44 is a cylindrical plunger 46 which extends into the bore 142 and is there provided with an enlarged cylindrical head 48 freely slidably but relatively closely received therein.

AThe outer end of the plunger 46, that is that end disposed towards the blind end of the bore 44, ls machined off on one side thereof in a plane parallel to its axis so as to provide a flat diametrically disposed surface 50 provided with a-n upstanding key 52 formed integrally thereon and disposed at an oblique angle with respect to the axis ofthe plunger 46. The outer end portool is provided with a transverse opening 54 of rectangular section therethrough and while the axis of this opening may be disposed perpenoicularly with respect to the axis of the main body portion it is preferably and thus shown disposed at an oblique angle to a plane perpen dicular to such axis. As best illustrated in Fig. 5 it will be noted thatone sideface' of the opening 54 lies in the same diametrical plane as the surface 50 on the plunger 46. Longitudinally slidably and relatively closely received in the opening 54 is a cutter blade 56 of the same cross-sectional configuration as -theopening 54 and having a cutting edge 58. The cutter blade 56 is provided with a groove 60 in that face thereof which lies in contact withthe surface 50 of such size and disposed at such an angle as to closely but slidably receive the key 52 therein.

As will be appreciated from the above description, with` the construction described upon axial movement of the plunger 46 the interengagement of the key 52 with the grooves 60 ing such that movement of the plunger 46 outwardly or to the left as viewed in Figs. 3 `and' 4 will cause the cutting edge 58 of the blade 56 to be projected to a position such, for instance as illustrated in Fig. 4, will cause the blade 56 'and .movement in the opposite direction to be retracted or withdrawn to a position such, for instance, 'as lillustrated in Fig. 3. blade 56 being of the same cross-sectional conl guration as the opening 54 and being closely The cutter -received therein, serves to seal the space between it and the walls of the openings 54 against the infiltration of dust, dirt or other foreign material to the bore 44 there past.

A coil spring 64 surrounding the plunger 44 within the bore 42 and maintained under compression between the shouldered end of the bore 42 and the opposed end of the enlarged head 48- constantly urges the plunger 46 to the right as .bar member.

viewed in Figs. 3 and 4 and vconsequently the cutter blade 56 towards aretracted position such. as illustrated in Fig. 3. As will be apparent if sufficient movement of the plunger 46 in this direction is permitted the key 52V will be withdrawn from the groove 68 in the cutter blade 56 and will permit the cutter blade 56 to be withdrawn from the tool, this fact being utilized both in assembly of the -tool and in removal of the blade 56 for sharpening or replacement. Ordinarily, however, it will be understood that the retracting movement of the plunger 46 is limited during normal operation an amount insufficient to withdraw the key 52 from the groove 68 and, therefore, disengagement of the plunger 46 from the cutter blade 56.

In orderto limit retracting movement of the plunger 46v during normal operation, the enlarged head portion 48 of the plunger 46 adjacent its inner or right hand end as viewed in Figs. 3 and 4 is provided with a diametrical opening 68 therethrough. Within the opening 68 iss-'slidably received a transversely extending bar or member 18 the opposite outer ends of which are provided with threads. The outer ends of the bar or member 18 project through a diametrical slot 12 formed in the main body portion 34, and the length of the bar or member 18 is such that both threaded end portions thereof project radially outwardly of the surface of the'portion 34 a distance equal to the depth of the threads on the of the slots 12 axially o f the tool is materially greater than the dimension of the bar member 18 axially of the tool so as to permit axial movement of the plunger 46 in the tool between the limits of movement of the bar 18 in the slot 12. It will be appreciated that the spring 64 normally urges the plunger 46 and the enlarged `tool is` a sleeve member or nut' 14 which is interiorly provided vwith screw threads with which the screw threadson the outer ends of the` bar member 18 are operatively engaged. The threaded engagement of the bar 18 and the nut 14 thus constrains the nut 14 to equal movement with the plunger 46 axially of the tool but it will be appreciated that by rotating the nut 14 with respect to the main body portion of the tool it will be axially displaced with respect to the bar 28 because of its threaded engagement therewith and,1 accordingly, the axial position of the nut 14 may thus be varied with respect to the plunger 46. The exterior surface of the nut 14 is preferably knurled as illustrated inv Fig. 2 lto permit manual grasping of the same to effect rotation thereof. The inner or righthand end of the nut 14 as illustrated in Figs. 3 and 4 is adapted to It will be noted `that the lengthA vsurface, of the keys.

extend into engagement with the'shoulder 36 provided between the portions 32 and 34 of the main bodyof the tool. This contact of the nut 14 with the shoulder 36 acts, as illustrated in Fig. 3, through the bar 18 to limit the retractf ing movementof the plunger 4 6, or movement to -the right as viewed in Figs. 3 and 4, under the inuence of the spring 64, and thus acts to limit vthe amount of retraction of the cutter blade 56 into the tool when the tool is in retracted position.

Axially slidably but relatively closely received in the bore 42 immediately inwardly or to the right of the enlarged head 48 of the plimger 46,

as viewed in Figs. 3 and 4, is a short plunger 88 the outer or lefthand end of which is normally axially spaced from the end of the enlarged head 48 of the plunger 46, and the inner or righthand end thereof as viewed in Figs. 3 and 4 is Iformed to provide a 4frusta-conical surface 82. The

vplunger 88 is provided with a diametrlcal slot 84 therethrough in which is received a diametrically extending bar or member 86 and the main body portion 34' visv provided with a diametrical slot 88 therethrough rearwardly, or to the right as viewed inv Figs. 3 and 4, from the slot 12 and through which the ends of the bar 86 project. The outer ends of the bar 86 project outwardly beyond the circumference of the main body porf tion 34 and are received in short axially directed.- recesses or grooves 98 formed in the inner wall of the nut 14 and opening onto the rear or rightf 4 the forward ends, of the grooves or recesses 98 in the nut 14 provide stops or shoulders against which the radially outer and axially forward margins of the bar 86 are adapted to contact.

The main body portion 32 of the tool is also provided with a diametrical slot 84v therethrough in which a pair of opposed keys 96 are relatively closely but slidably received for radial movement therein. The keys 86 are duplicatesof each other and are arranged in opposed relation in lthe slot 94 and are constantly urged outwardly away from one another by means of a coil compression spring 98 the opposite ends of which are received in opposed pockets formed in the opposed end The bore l42 immediately inwardly or Ito the right of the keys 96 as viewed in Figs. 3 and 4 is closed by a plug |88 which not only serves to additionally back up the keys 96,

- but-also serves to prevent inadvertent projection beveled in Aa radially inwardly .and axially outer direction as at |84 and this last end of each of the keys 96 is adapted to project radially .outwardly beyond the outer surface of the body portion 32 when the tool'is in inoperative position with the cutter blade 56 retracted.

It will be understood from the description thus far given that if the keys 96 are urged radially inwardly toward one another they will act through their beveled faces |02 contacting the frusto-conical portion 82 of the plunger 80 to move the plunger 80 outwardly or to the left as viewed in Figs. 3 and 4. When thev plunger 80 is thus moved towards theleft as described it will carry the bar member 86 therewith'and the bar member 86 in moving a corresponding distance to the left will act against the ends of the grooves or recesses 90 in the nut 14 to move the nut 14 to the left a corresponding distance. The nut 14 in thus moving to the left will act through the bar member 10 and head 60 of the plunger 46 to move the plunger 46 a corresponding distance to the left and this movement of the plunger 46 will act to project the cutter blade 56 outwardly with respect to the axis of the tool as previously described.

It will be appreciated that the amount which the cutter blade 56 will thus be projected in a generally radial direction with respect to the axis of the tool will depend upon the amount of relative axial reciprocation imparted to the plunger 46 and the parts thus described forming a driving connection between it and the keys 96, and the relative axial movement of which with respect to the body of the tool will depend upon the amount of radially inward movement imparted to the keys 96. It will also be appreciated that for a given amount of radially inward movement of the keys 96, the blade 56 will be projected radially to the same extent under all circumstances, 'Consequently in order to adjust the tool so that the cutter blade 56 will machine a bore of greater or lesser diameter than then set for, the initial or inoperative position of the blade must be\ adjusted so that upon a given projection of the cutter blade the required diameter of bore will be machined by the blade.

' This inoperative or retracted position of the cutter blade 56 is, of course, adjusted by rotating the nut 14 to either advance or retract the plunger 46 dependingupon whether it is desired to machine a larger or a smaller bore respectively. In other words by rotating the nut 14 vin one direction it will act through the bar 10 to advance the plunger 46 and, therefore, project the blade 56 to a greater extent from the tool in its inoperaitve condition and upon turning the nut 14 in a reverse direction it will retract the blade 56 to a further extent into the tool.

In order to facilitate the thus above described adjustment and to enable the amount of adjustment to be visually determined, spaced graduations ||0 are provided circumferentially around the outer righthand end of the nut 14, as best illustrated in Fig. 2, and an indicator mark ||2 is provided on the body portion 32 for cooperation therewith. The pitch ofthe threads on the interior of the nut 14 are preferably so correlated with the angularity of the key 52 and the angularity of the blade 56 that one complete rotation of the nut 14 will radially project or retract the cutting edge 58 of the blade 56 an even part of an inch, for instance lyooth of an inch, in which case if graduations |I0 are provided with one hundred subdivisions movement of the nut 14 through the distance of one graduation only will vary the radial position of the cutting edge 56 oooth of an inch. It will, of course, be appreciated that the radial movement imparted to the cutting calife 5B of the cutter blade 56 upon a complete rotational movement of the nut 14, and, accordingly, the number of graduations ||0 employed, may b e varied to suit the desires of the individual designer.

It will likewise be appreciated that the amount which the cutting edge 58 of the blade 56 will be projected in a radial direction upon contraction of the keys 96 will depend upon the amount of contraction or radially inward movement of the keys 96 after contact with the surface 82 of the plunger 80. The means preferably employed to effect a contraction of the keys 96 is a collar or sleeve which is forced over them or through which the tool passes or is forced. In other words by forcing a collar or sleeve over the nut portion 14 and the body portion 32, and assuming that the bore of the collar or sleeve is less than the distance between the opposite outer ends of the keys 96 when in expanded condition,` the act of forcing the sleeve or collar over the keys 96 will -cause the keys 96 to be advanced toward one another and thereby effect movement of the various parts of the tool in the manner previously described to cause the cutter blade 56 to be projected in a generally radial direction upon the tool.

If the tool is employed for a boring operation while the keys 96 are thus retracted, and assuming that they are contracted to this same extent-during the continuance of the boring operation, the bore machined by the cutter blade 56 will be of a uniform diameter. Should, however, the sleeve or collar employed for contracting the keys 96 have a bore of varying diameter and the tool is fed axially relative to both the work and the sleeve or collar when the cutter blade is expanded by the sleeve or collar, it will be appreciated that the bore thus machined by the cutter blade will vary an amount proportional to the variation in the diameter of the bore of the sleeve or collar because of the changing relation of the keys 96 to each other as controlled thereby. Likewise if the sleeve or collar is provided with 'a plurality of cylindrical bore sections of different diameters which will contract the keys 96 different amounts during the passage of the keys 96 therethrough, and the bore machined by the cutter blade 56 will vary in diameter in proportion to the variations in diameter of the various portions of the bore of the sleeve or collar.

As a matter of illustration the particular sleeve or collar |20 illustrated in the drawing for the purpose of contracting the keys 96 to expand the tool is shown as being provided with a cylindrical bore |22 of constant diameter for effecting expansive movement of the tool, the use of other sleeves or collars having bores of other shapes, as

for instance uniformly or otherwise varying or stepped surfaces, being thereby made apparent to those skilled in the art.

In employing a sleeve such as the sleeve |20 for the purpose of expanding the tool during operation, the sleeve is preferably caused to be forced over the keys 96 as' an incident to the feeding operation of the tool With respect to the Work. For instance, `in the application of the tool to a machine of the type illustrated in Fig. 1 in which the toolis rotated by the spindle I4 but the relative feed between the tool and the Work is effected by moving the work in a direction axially of the tool, the arrangement illustrated in Fig. 1 and more clearly brought out in Figs. 3 and A4 is preferably employed. In other words and particularly referring to Figs. 3 and 4 and vcylindrical bore |26 in the work 20 and the extreme outer end of the portion 40 is rotatably received in andA guided by a bushing I28 in the pilot 22 which thus forms an outboard bearing for the tool. The outer end of the sleeve or collar |20 is enlarged and interiorly annularly recessedat |30 to receive a thrust bearing |32 therein and the sleevel |20 is placed around the tool and positioned with the thrust bearing |32 in contact with the stop collar 28. Assuming that it is desired to relieve the bore |26 in t-he work 20 over a distance and to a depth indicated by the dotted lines |34, thelength of the sleeve |20 or else the position of the work 20 with respect to the.

stop collar 28 will `be such that as the tool is advanced into the bore |26 of the work 20 the cutter bladewill reach a position such as indicated in Fig. 3, and in which the cutting edge 58 of the cutter blade 56 is at the righthand limit of the portion |34 which it is desired to relieve at the moment, the keys 96 simultaneously contact the entering end of the sleeve or collar |20 and the 'surface 82 of the plunger 80. In this connection it will be noted that the entering end of the sleeve or collar |20 is beveled off as at |40 for complementary engagement with the beveled ends |04 of the keys 96. After the tool has'reached the position illustrated in Fig. 3 and as above described, it will be appreciatedthat upon continued axial feeding movement of the work relative to the tool .the keys 96 will, during the initial feeding movement, be contracted or urged toward one another to eiect expansion of the tool and,

therefore, radial projection of the cutter blade 56 until the extreme outer ends of the keys 96 are confined within the cylindrical bore |22 of the sleeve |20, at which time the cutter blade 56 will have been projected to the desired radial extent to effect machining of the relief |34 in the work ,20 to the desired depth, and during continued relative feeding movement between the tool and work while the keys 96 are contained Within the cylindrical bore |22 of the sleeve |20 the cutter blade 56 will machine the relief |34 in the Work 20 at a constant diameter.v

The axial length of the relief |34 in the work 20 may be controlled in one of several different ways. For instance the boring machine may be so controlled that after the carriage or table I8 carrying the work 20A has advanced towards the head I2 a sufficient distance it may be reversed in direction of feed whereby the blades 56 will be maintained in an expanded condition until it reaches the relative position illustrated in Fig. 4

whereupon further reversal of the feeding movement will wi-thdraw'the keys 96 from under the collar |20 and permit their expansion and, therefore, contraction of the cutter blade 56 during the remaining withdrawing movement vof the tool from the Work. 'In employing vthis last described arrangement vit will be necessary to employ some suit-able or conventional means for maintaining the axialposition of the feed 20 against the inner face of the stop collarv 28 as will be readily appreciated.

On the other handthe length of the bore |22 of the feed 20 may be formed to correspond with the length of the relief |34 desired in the work,

the remaining bore of the sleeve I20beinggreater y than the bore |22 so that when the keys 96 have travelled through the sleeve |22 a distance corresponding with the desired length of theA relief |34 in the work 20, they will pass beyond the end of the bore I22 and thereby permit itto expand and effect contraction of the tool thus terminating the machining of the relief. the particular construction illustrated in Figs.V 3 and 4 in which it will be noted that the length of the cylindrical bore |22 of the sleeve |20 corresponds with the length of the relief I34 in the work 20. The sleeve |20 in this case is provided with a second bore |42 at the outer end of the bore |22 perbore |22. With this last described construction unless the shoulder formed between the bores I 22 and |42 is beveled in a direction oppositeto the bevel |40 and the corresponding rear edges of the keys 96 are correspondingly beveled so as to permit withdrawal of the tool rearwardly with respect to the sleeve |20, in order to re-condition the machine for subsequent operations it will be necessary to withdraw the boring tool from` the machine spindle,v withdraw the sleeve |20 from the rear or inner end of the boring tool, then replace it upon the forward end of the boring tool and replace .the boring tool', in the machine spindle.

From the above description it will be understood that the construction of the tool-described is such as to. permit the tool to be inserted in a bore in a piece of Work to a desired position, the tool expanded so as to remove metal from such bore to provide a relief therein if desired or to machine the entire bore out to la uniform or a varying diameter during a continued feeding movement between the tool and work, and that the expansion of the tool and consequently the diameter of the bore machined thereby occurs y after having been fed axially past the end of the with respect to each otheras they naturally will be when properly constructed, adjustment of the tool to change the diameter of the bore being machined it may be manually adjusted and visually determined to a highly accurate degree. It is to be particularly noted that the vparticular arrangement employed for effecting expansion and contractive movements of the cutter blade 56, namely by employing a relatively small plunger 46 and machining the iiat 50 and key 52 thereon forv engagement with a groove in the cutter blade, does not materially detract from yet provides an efficient and accurate connection betweenthe two. Furthermore, in view of the the strength of the plunger or cutter blade and vention capable of operating in materially small- 4 er bores .than has heretofore been possible with previously suggested constructions of a. similar type. It will also be appreciated that the tool and the apparatus employed for controlling theexpansion thereof and continuance of expansion during a predetermined feeding movement is such as to adapt it to a wide range of variations in Formal changes may be made in the specific embodiment of the invention described without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

What I claim is:

1. In a boring tool, in combination, a main body portion, a plunger within said main body portion mounted for movement axially of said main body portion, a cutter blade supported and guided by, said main body portion for movement in a direction transverse to the axis of said main body portion, means interconnecting said cutter lblade and said plunger for simultaneous movement in the direction of their respective lengths, means supported by said main body portion in axially spaced relation thereon with respect to said cutter blade for movement towards and away from the axis of said m'ain body portion, means interconnecting the last mentioned means with said plunger so constructed and larranged as to positively move said plunger in at least one direction upon movement of the rst mentioned means in at least one direction relative to said axis of said main body portion, and means having a relative axial movement with respect' to said main body portion cooperable with said'second mentioned means during said relative axial movement to control the position of said second mentioned means with respect-to the axis of said main body portion.

2. In a boring tool, in combination, a main body portion, a plunger within said main body portion mounted for movement axially of said main body portion, a cutter blade supported and guided by said main body portion for movement in a directionrtransverse to the axis of said main body portion, means interconnecting said cutter lblade and said plunger for simultaneous move# ment in the direction of their respective lengths, means supported by said main body portion in axially spaced relation-thereon with respect to said cutter blade for movement towards and away from the axisof said main body portion, means interconnecting the last mentioned means with said plunger so constructed and arranged as to positively move said plunger in one -direction upon movement of the first mentioned means in one direction relative to said axis of said main body portion, and resilient means constantly urging said plunger in a direction opposite to the direction imparted thereto by the second mentioned means.

3. In a boring tool, in combination, a main body portion, a plunger within said main body portion mounted for movement axially of said main body portion, a cutter' blade supported and guided by said main body portion for movement in a direction transverse to the axis of said main y body portion, means interconnecting said cutter blade and said plunger for simultaneous movement in the direction of their respective lengths, means supported by said main body portion in axially spaced relation thereon with respect to said cutter blade for movement towards and away from the axisof said main body portion,

l means interconnecting the last mentioned means with said plunger so constructed and arranged as to positively move said plunger in one direction upon movement of the first mentioned means in one direction relative to said axis of said main body portion, and means in the connection between the second .mentioned means and said 5 plunger operative to eiect adjustment in the axial position of said plunger in said main body portion independently of movement of said second mentioned means.

4.'In aboring tool, in combination, a main 10 body portion, a plunger within said main body portion mounted for movement vaxially of said main body portion, acutter blade supported and guided by said main body portion for movement in a direction transverse to the axis of said main 15 body portion, means interconnecting said cutter blade and said plunger for simultaneous movement in the direction of their respective lengths, means supported by said main body portion in axially spaced relation thereon with respect to 20 said cutter blade for movement towards and away from the axis of said main body portion, means interconnecting the last mentioned means with said plunger so constructed and arranged as to positively move said plunger in one direction upon 25 movement of the first mentioned means in one direction relative to said axis of said main body portion, and means in the connection between the second mentioned means and said plunger operative to effect adjustment in the axial position of said plunger in said main body portion independently of movement of said second mentioned means, comprising a nut threadably interconnected with said plunger and means operatively connecting said nut with said rst mentioned means.

5. A boring tool comprising, in combination, a main body portion, a cutter blade supported and guided thereby for effective movement towards and away from the axis of said main body portion, means interiorly of said main body portion cooperating with said cutter blade to control said movement thereof, a nut exposed exteriorly of said main body portion, a threadable connection between the rst mentioned means and said 45 nut, said nut being mounted for both rotatable andv axial movement on said main body portion, an axially disposed stop, spring means constantly urging said nut towards said stop, control means supported by said mam body portion and pro- 50 .Jectable radially outwardly therebeyond, and means interconnecting said control means and said nut for effecting movement of said nut and said rst mentioned means against the force or said spring upon movement of said control means 55 v towards the axis of said main body portion.

6. A boring tool comprising, in combination, a main body portion, a cutter blade supported by said main body portion and movable towards and away from the axis of said main body portion,

va plunger within said main body portion, means operatively interconnecting said plunger and cutter blade for inter-related movement in the direction of their respective lengths, a sleeve-like member rotatably and axially slidably mounted 65 on said main body portion, means effecting a. threaded connection between said plunger and said sleeve-like member whereby -to permit ad the axis thereof and normally projectingl outwardly beyond the circumference of saidmain body portion cooperable with said second plunger for eiiecting movement thereof axially of said main body portion upon movement of the last mentioned means towards the axis of said main body portion;

7. Boring apparatus including, in combination, a boringtool adapted for relative rotation and relative axial advancement with respect to a piece of work and having a main body portion, a cutter blade supported and guided by said main body portion for movement toward and away from the axis of said main body portion, means supported by said mainv body portion for movement toward and away from the axis thereof and normally projected radially beyond the circumference of said main body portion, means interconnecting said cutter blade and the first mentioned means for correlated movement with respect to the axis of said main body portion, and means associated with said tool for controlling the position of the by said main body portionfor movement toward and away from the axis thereof and normally projected radially beyond the circumference of said main body portion, means interconnecting said cutter blade and the rst mentioned means for correlated movement with respect to the axis of said main body portion, and means associated with said tool for controlling the posi-tion of the second mentioned means with respect to the 'axis 5 of said main body portion during axial movement of said main body portion, comprising a sleeve surrounding said tool and adapted for the same relative movement as the work. axially of said tOOl. 1

9. Boring apparatus including, in combination, o a boring tool adapted for relative rotation and relative axial advancement withrespect to a piece of work and having a main body portion, a cutter blade supported andv guided by said main body 15 portion for movement toward and away from the axis of said main body portion, means supported by said main body portion for movement toward and away from the axis thereof and normally projected radiallybeyond the circumference of 20 said main'body portion, means interconnecting said cut-ter blade and the rst mentioned means for correlated movement withrespect to the axis of said main body portion, and means associated with said tool for controlling the position of the 25 second mentioned vmeans with respect to the axis of said main body portion during axial movement of said main body portion, comprising` a sleeve adapted to surround said tool and having a bore adapted to engage the lsecond mentioned 30 means during relative advancement of said tool with respect to the work thereby to control both. the extent and duration of radial projection of the second mentioned means with respect to the axis of said main body portion during travel 35 therethrough. Y

WILLIAM K. YOUNG. 

